public class DaylyData {

private Date date;
private List<Integer> numersList;

public Date getDate() {
    return date;
}
public void setDate(Date date) {
    this.date = date;
}
public List<Integer> getNumersList() {
    return numersList;
}
public void setNumersList(List<Integer> numersList) {
    this.numersList = numersList;
}

public Map<Integer, Date> getIntToDate() {
    Map<Integer, Date> resultMap = new HashMap<>();
    for(Integer number : getNumersList()) {
        resultMap.put(number, getDate());
    }
    return resultMap;
}

resultList.stream().flatMap(entity -> entity.getIntToDate());